The U.S. Congress should kill the section of the Patriot Act that has allowed the National Security Agency to collect millions of phone records from the nation’s residents, instead of trying to amend it, a civil liberties advocate said Friday.

Section 215 of the Patriot Act, which allows the NSA to collect phone records, business records and any other “tangible things” related to an anti-terrorism investigation, expires in June, and lawmakers should let it die, said Neema Singh Guliani, legislative counsel for the American Civil Liberties Union.

The House of Representatives Judiciary Committee on Thursday voted to approve a bill to amend that section of the anti-terrorism law. The USA Freedom Act would end the NSA’s bulk collection of U.S. phone records by narrowing the scope of the agency’s searches, backers of the bill said.

The USA Freedom Act “does not go far enough” to protect U.S. residents from surveillance, Guliani said during a debate about section 215 hosted by the Congressional Internet Caucus. While the bill doesn’t allow NSA searches by state or even zip codes, it would still allow the search of the records of “several hundred people who might share an IP address” over a wireless network, or records on an entire company, she said.

The bill also doesn’t require the NSA to purge the records of innocent people it collects while targeting someone with suspected ties to terrorism, she said. “Section 215 was an unprecedented expansion of intelligence agency authority,” she added. “It’s time for that provision to sunset and return to an infrastructure that’s more respectful of privacy.”

Other speakers defended the USA Freedom Act, saying it makes significant improvements in protections of privacy and civil liberties. The bill isn’t perfect, but it’s a good first step toward fixing overzealous surveillance practices, said Chris Calabrese, senior policy director at digital rights group the Center for Democracy and Technology.

Without passage of the USA Freedom Act, some lawmakers will push for Congress to renew section 215 without any changes, he said. Senate Majority Leader Mitch McConnell, a Kentucky Republican, and Senate Intelligence Committee Chairman Richard Burr, a North Carolina Republican, introduced a bill in April to reauthorize section 215 with no new limits on NSA records collection.

The USA Freedom Act appears to be legislation that the NSA and other surveillance agencies can support, said Robert Litt, general counsel at the Office of the Director of National Intelligence. Congressional action that lets section 215 expire would, however, hurt anti-terrorism efforts at the NSA and other agencies, he said.

In addition to the phone and business records provisions in section 215, the FBI uses that section of the Patriot Act to target surveillance at individual terrorism suspects and to gain access to so-called roving wiretaps that follow a suspect instead of a specific device, he said. Terrorism suspects can change mobile phones frequently, he said.

Litt was asked multiple questions about how surveillance and law enforcement agencies use section 215 to track terrorists. He declined to directly answer the questions posed by panel moderator Ellen Nakashima, a Washington Post reporter, saying specific methods were classified.

“The question is, is this a valuable counterintelligence and counterterrorism tool?” he said. “It is, clearly. It’s not true that we could do the same thing under other authorities. There are kinds of records you could not get.”

When Nakashima asked what kinds of records the NSA could no longer collect, Litt declined to name them. “I can’t talk about them,” he said.

Nakashima later asked Litt if the NSA, in the past year, had found any valuable information related to a terrorism investigation through its phone records collection program.

“So I will answer that question with a one-word answer and not take any followups,” Litt said. “Yes.”

Even with calls for more transparency, the NSA will “never” reveal how it obtained information about a particular terrorist suspect by searching a specific set of records, he said. Those kinds of techniques are classified, he said.